Mapping Arterial Perforators Within the Breast During Mammoplasty

Despite breast cancer being one of the most frequent affecting women worldwide, it is also one of the most curable. Its multimodality treatment is based on surgery, radiotherapy and systemic therapy.

Breast conservation has evolved thanks to the utilization of mammoplasty techniques to achieve better aesthetic results - known collectively as 'oncoplastic' when applied to cancer surgery.

The key considerations in oncoplastic surgery are: tumour characteristics (extent, location) and reconstituting the aesthetically acceptable breast shape as well as nipple-areola complex (NAC) preservation. The former is vital to achieve clear resection margins to optimise local control. Planning is aided by imaging with ultrasound, mammography and often MRI. NAC preservation is a priority and expectation of patients and surgeons alike developed in the field of aesthetic breast surgery by plastic surgeons.

The attachment of any structure to the body by its nourishing blood supply (arteries and veins) is known as a 'pedicle'. The anatomy of the pedicle and its preservation is key to preservation of the NAC which has a well understood blood supply albeit with variations across patients and well-described patterns (ref). To preserve the NAC as part of a cancer resection and aesthetic breast re-shaping, a pedicle must be fashioned and the NAC successfully re-positioned to restore the aesthetic balance of the newly shaped (and often lifted) breast.

The aim of this study is to determine if by use of doppler (acoustic or colour flow modalities) to map the blood vessels supplying the NAC (for each individual patient), surgeons and trainees can construct a safe pedicle with greater confidence and ease, reducing the concern about diminishing its blood supply which could lead to NAC necrosis and loss. We would like to study the nipple blood supply as it pertains to each patient before surgery using acoustic doppler (AD) and colour doppler imaging (CDI). Each modality has its strengths and weaknesses and this evaluation aims to assess the contribution of each.

The most challenging part of therapeutic mammoplasty is the pre-operative planning. The surgeon must consider (1) localization of the tumour location and extent, (2) re-shaping of the remaining breast parenchyma and (3) placement of the vascularized the NAC and pedicle.

Several studies have been done regarding NAC vascularization and its variation between not only each person, but also each side (right versus left). Most studies were on cadavers3, MRI 4or CT angiography5. On the other hand, Seitz et al6 pointed out the predominancy of the NAC vascularization based on preoperative MRI in the breast without cancer. Specifically, they split all 56 breasts into 5 categories: type I medial, type II lateral, type III central, type IV inferior, and type V mixed. Moreover, they highlighted that the majority of NACs were supplied mostly by medial vessels. Basaran et al7 evaluated sixteen patients with severe gigantomastia and they marked the vessel locations before surgery by using Doppler ultrasonography.

Given the variation between people and their breasts, in this SE we would like to map preoperatively the NAC vascularization to understand if it could assist the surgeon's plan or even enable them to modify the NAC pedicle design. The mapping will be done by both CDI and AC. We will use both techniques to understand if there will be any difference in their accuracy and to determine if 1 modality alone will suffice.

Whilst both methods (acoustic and colour flow doppler) are used selectively in cases by some surgeons, this SE will specifically if routine use incorporated into the procedure will systematically facilitate pedicle design. The doppler carries no risk to the patient and is considered a tool to facilitate surgery rather than an intervention beyond standard of care.

Specifically, acoustic doppler (AC) - is a hand-held device, easy to use intra-operatively which gives an audible signal in real-time to enable marking of the exact location of a blood vessel at a given point (or along a specified line) within the tissue / under the skin.

Colour doppler imaging (CDI) will additionally give visual information which includes the calibre and depth of the vessel and enables the entire course of the vessel and any connections to be mapped relatively easily.

In reality, when the design and shaping of the NAC pedicle is undertaken during the operation, ideal placement / movement of this structure may be restricted by the surrounding tissue attachments which the surgeon may be fearful of dividing in case a critical artery is divided in the process (compromising the NAC perfusion). Knowing the exact location of the artery will give the surgeon confidence in knowing how far such tissue mobilisation can be safely undertaken.

Some therapeutic mammoplasties also involve creation of a 'secondary pedicle' which consists of breast tissue - again mobilised on a pedicle which must be moved within the breast to fill a defect created by the cancer resection. A secondary aim of this SE will be to map the principle arteries which supply that tissue as well.

In summary, this SE aims to establish the benefits of an ad-hoc practice by careful documentation of consecutive cases prospectively during surgery for mammoplasty where NAC or secondary pedicle mobilisation is required.